package cn.edu.scau.cmi.liujiaming.chapter09;

public class EncryptAndDecrypt {   
	   public String encrypt(String sourceString,String password) { //加密算法
	       char [] p= password.toCharArray();
	       int n = p.length;
	       char [] c = sourceString.toCharArray();
	       int m = c.length; 
	       for(int k=0;k<m;k++){
	            int mima=c[k]+p[k%n];       //加密
	            c[k]=(char)mima; 
	       }
	       return new String(c);    //返回密文
	    }
	   public String decrypt(String sourceString,String password) { //解密算法
	       char [] p= password.toCharArray();
	       int n = p.length;
	       char [] c = sourceString.toCharArray();
	       int m = c.length; 
	       for(int k=0;k<m;k++){
	           int mima=c[k]-p[k%n];       //解密
	           c[k]=(char)mima; 
	       }
	       return new String(c);    //返回明文
	   }
	}